This application is the national phase under 35 U.S.C. xc2xa7371 of PCT International Application No. PCT/JP97/04640 which has an International filing date of Dec. 16, 1997 which designated the United States of America.
1. Field of the Invention
The present invention relates to a method of manufacturing a pellicle and a jig for manufacturing a pellicle.
2. Description of the Related Art
In manufacturing a semiconductor device such as an LSI and a VLSI, and a liquid crystal display plate, or the like, patterning for forming wiring called a pattern is performed by photo-irradiation onto a semiconductor wafer or an original plate for a liquid crystal display plate. During the patterning, a so-called mask (an original plate for exposure) is used, and if even a very small amount of dust is present on the mask, the dust makes an adverse effect on patterns and results in causing the semiconductor device or the liquid crystal display plate not usable.
For that reason, as well known, patterning is performed in an especially dustless room which is called a clean room. However, even in such clean room, it is still difficult to remove microscopic dust completely.
Accordingly, in order to remove dust strictly, a cover called a pellicle is attached to the surface of the mask for protecting the mask from dust.
The pellicle is a body consisting of an organic transparent thin film pasted on a specified frame, and the pasted thin film is generally called a pellicle film, and further, the specified frame on which the pellicle film is pasted is called a pellicle frame.
Although a method of manufacturing a pellicle is known as disclosed in, for example, Japanese Patent Application Laid-Open Publication No. 7-281421, this manufacturing method will be briefly described below.
(1) An organic thin film such as a nitro-cellulose, ethyl cellulose, or the like which becomes a pellicle film is temporarily attached to another frame, which is larger than the specified frame which becomes a pellicle frame, in a covered-state.
(2) An adhesive is coated on one of side edges of the specified frame.
(3) The another larger frame coated with the organic thin film of the (1) is brought to approach the adhesive-coated one edge of the (2) from above, and the organic thin film of the (1) is attached to the adhesive-coated one edge of the (2), and then the organic thin film is transferred from the another frame to the specified frame by separating the another frame from the specified frame. In this case, the organic thin film is radially protruded from the edges of the specified frame. The protruded portion is an unnecessary portion which cannot be used as the pellicle film, and non-protruded portion is an effective portion which functions as the pellicle film. Hereinafter, the unnecessary portion is referred to as xe2x80x9cthe unnecessary filmxe2x80x9d as against the pellicle film.
(4) The pellicle is formed by trimming the unnecessary film along the above-mentioned specified frame.
Meanwhile, as a means for trimming the unnecessary film, there have been known a physical method including a cutter such as a knife, a laser beam for cutting and other physical method, and a chemical method in which the unnecessary film is dissolved by a dissolving liquid.
With the physical method, although the unnecessary film can be removed within a short period of time, exceedingly minute dust such as chips, etc. will remain along the trimmed edges.
If the pellicle, in this state of having the remained dust, is used to cover a mask, it would occur that the dust drops from the pellicle, and adheres to a pattern. Then, as described above, a semiconductor device or a liquid crystal display plate becomes useless because of inferior products.
Accordingly, heretofore, efficiency of removal is enhanced by wiping the remained dust with a solvent or an adhesive tape after removing the unnecessary film with the above-mentioned method, but further efficiency of removal is demanded.
On the other hand, with the chemical method, although adverse influences by dust such as chips are not caused, it takes a long time for removing the unnecessary film in comparison with the physical method.
For that reason, there has been desired a new technology having advantages of both physical and chemical methods, in which disadvantages of both methods are eliminated.
The present invention has been made in view of the above-mentioned problems, and, therefore, an object of the invention is, in manufacturing a dust cover, namely, a pellicle, for a mask being used in a so-called in patterning in manufacturing a semiconductor device, a liquid crystal display plate and the like, to provide a method of manufacturing a pellicle and a jig for trimming an unnecessary film, whereby exceedingly minute dust such as chips, etc. which is produced in a process of cutting off the unnecessary film, can be suppressed as much as possible, and the cutting-off process can be accomplished within a short period of time.
A method of manufacturing a pellicle according to the present invention is:
(1) a method of manufacturing a pellicle comprising the steps of:
temporarily coating a thin film, which is a constituting member of a pellicle which is a dust cover for a mask used in patterning in manufacturing a semiconductor device or a liquid crystal display plate, on a frame larger than a specified frame which is another constituting member of the pellicle;
coating an adhesive on the specified frame in advance;
overlapping said larger frame on the specified frame coated with said adhesive;
adhering the thin film which has been temporarily coated on said larger frame to the specified frame by the adhesive;
transferring the thin film coated on the larger frame to the specified frame from the larger frame; and
removing a portion of the transferred thin film, the portion which is protruded from the specified frame, with a physical trimming means, and
wherein a coating material, consisting of an organic solvent and a specified resin dissolved therein, the coating material which is a thermo-setting type adhesive or an ultraviolet curing type adhesive which can suppress dust produced in cutting off the thin film and make not to remove the dust from the thin film, is supplied to a cut-off portion which is intended to be cut off, by said physical trimming means, at the same time or before cutting off the thin film with the physical trimming means.
Accordingly, with the method of manufacturing a pellicle of the present invention, before removing the protruded portion of the thin film transferred to the specified frame with the physical trimming means, the cut-off portion intended to be cut off is coated with the coating material. Consequently, even though exceedingly minute dust(s) is (are) produced in a trimmed portion of the thin film, the minute dust(s) is(are) mixed with the coating material, thereby the dust cannot move due to an adhesive force of the coating material. Thus, the minute dust comes into a state that it is attached to the trimmed portion of the thin film. Therefore, it is possible to suppress to the utmost drop of the minute dust such as chops onto a pattern. Further, the protruded portion is removed by the physical trimming means, and trimming work can be finished within a short period of time.
The method of manufacturing a pellicle may be carried out in the following modes.
(2) The coating material is a thermo-setting type adhesive or an ultraviolet curing type adhesive which is applied to and covering a cutting surface of the thin film, thereby to suppress dust produced in cutting off the thin film with the physical trimming means and not to remove the dust from the cut thin film.
(3) The coating material is a saturated solution which consists of a specified organic solvent and a specified resin saturatedly dissolved therein.
(4) The resin contained in the coating material is immersed in the organic solvent for at least five hours or longer, and, preferably, 12 hours or longer at a temperature in the range of 20-25xc2x0 C.
(5) The saturated solution contains the resin at a ratio of 1-20 parts by weight, preferably 2-9 parts by weight, based on 100 parts by weight of the organic solvent.
(6) The resin is a resin material which is identical or similar to the material of the thin film.
(7) The resin is a resin material selected from a cellulose derivative, a silicone resin, an epoxy resin, an acrylic resin, and a fluorine-containing resin.
(8) The organic solvent is a solvent selected from a ketone solvent, a low fatty acid ester solvent, and a mixed solvent composed of a ketone or ester and isopropyl alcohol.
For the ketone solvent, there are exemplified methyl ethyl ketone, methyl isobutyl ketone, acetone, and the like.
For the low fatty acid ester solvent, there are exemplified butyl acetate, isobutyl acetate, and the like.
In the case where a fluorine-containing resin is used, the organic solvent may be a fluorine solvent, such as CT-100, CT-130, CT-160, and CT-180 (all of which are the product names) manufactured by Asahi Glass Co. Ltd.; EF-L102, EF-L155, EF-L174, and EF-L215 (all of which are the product names) manufactured by Tochem Products Co. Ltd.; and IL-260 and IL-263 (all of which are the product names) manufactured by Tokuyama Co. Ltd.
(9) When the resin is a fluorine-containing resin, a fluorine solvent is used as the organic solvant.
(10) The coating material is continuously supplied by means for supplying the coating material attached to or incorporated in the physical trimming means.
(11) The coating material is applied to the cut-off portion intended to be cut off, by the means for supplying the coating material.
(12) The coating material is discharged to the cut-off portion intended to be cut off, by the means for supplying the coating material.
(13) A pipe body is used for the means for supplying the coating material.
(14) When the physical trimming means is moved in a direction for cutting off the thin film, the coating material is supplied at a position where the physical trimming means comes in contact with the thin film or from above that position.
(15) A blade or a needle is used for the physical trimming means.
(16) The blade has a single edge or a double edge which can cut the thin film along the specified frame. It is preferable that the blade is of a thin-blade sharp edge type.
(17) The needle is a needle with its head obliquely cut.
On the other hand, a jig is required for manufacturing a pellicle, and the jig used in the method of manufacturing a pellicle according to the present invention will be described below.
(18) A jig used in a method of manufacturing a pellicle comprising the steps of: temporarily coating a thin film, which is a constituting member of a pellicle which is a dust cover for a mask used in patterning in manufacturing a semiconductor device or a liquid crystal display plate, on a frame larger than a specified frame which is another constituting member of the pellicle; coating an adhesive on the specified frame in advance; overlapping said larger frame on the specified frame coated with the adhesive; adhering the thin film which has been temporarily coated on the larger frame to the specified frame by the adhesive; transferring the thin film which has been temporarily coated on the larger frame to the specified frame from the larger frame; and removing a portion of the transferred thin film, the portion which is protruded from the specified frame, with a physical trimming means.
Specifically, the jig is characterized in that it includes a coating material supply means for supplying the coating material, which consists of an organic solvent and a resin dissolved therein, to a cut-off portion which is intended to be cut off from the thin film, at the same time or before cutting off the thin film with the physical trimming means.
Accordingly, with the jig used in the method of manufacturing a pellicle of the present invention, before removing the protruded portion of the thin film transferred to the specified frame body with the physical trimming means, the cut-off portion intended to be cut off is coated with the coating material supplied by the means for supplying the coating material. Accordingly, even though exceedingly minute dust is produced in the cut-off portion of the thin film by cutting off, the minute dust is mixed with the coating material, and placed in a state that the dust cannot be removed from the cut off thin film due to an adhesive force of the coating material. Thus, the minute dust remains attached to the cut off portion of the thin film. Therefore, it is possible to suppress to the utmost dropping of the minute dust such as chops onto a pattern as in the conventional art. Further, since the protruded portion of the thin film is removed by the physical trimming means, a trimming work can be finished within a short period of time.
The jig used in the method of manufacturing a pellicle according to the present invention may also be configured as follows.
(19) The means for supplying the coating material is fitted to the physical trimming means.
(20) The means for supplying the coating material is a pipe body.
(21) The physical trimming means is a blade.
(22) The blade has a single edge or a double edge which can cut the thin film along the specified frame.
(23) The physical trimming means is a needle.
(24) The needle is a needle with its head obliquely cut.
(25) The needle is attached to the jig body, and a discharging port for discharging the coating material is formed in a root portion of the needle in the jig body.
(26) The coating material is a thermo-setting type adhesive or an ultraviolet curing type adhesive which is applied to and covering the cutting surface of the thin film, thereby to suppress dust produced in cutting off the thin film with the physical trimming means and not to remove the dust from the thin film.
(27) The coating material is a saturated solution consists of a specified organic solvent and a specified resin saturatedly dissolved therein.
(28) The resin contained in the coating material is immersed in the organic solvent for at least five hours or longer, preferably, 12 hours or longer at a temperature in the range of 20-25xc2x0 C.
(29) The saturated solution contains the resin at a ratio of 1-20 parts by weight, preferably 2-9 parts by weight, based on 100 parts by weight of the organic solvent.
(30) The resin is a resin material which is identical or similar to the material of thin film.
(31) The resin is a resin material selected from a cellulose derivative, a silicone resin, an epoxy resin, an acrylic resin, and a fluorine-containing resin.
(32) The organic solvent is a solvent selected from a ketone solvent and a low fatty acid ester solvent, when the resin is a cellulose derivative, a silicone resin, an epoxy resin or an acrylic resin.
(33) When the resin is a fluorine-containing resin, a fluorine solvent, such as, as described in (8) above is used as the organic solvent.
(34) The coating material is coated on the cut-off portion intended to be cut off, by the means for supplying the coating material.
(35) The coating material is discharged to the cut-off portion intended to be cut off.